Automobile clutch



Dec. 12, 1939. w. s. WOLFRAM AUTOMOBILE CLUTCH Filed June 14, 1937 2 Sheets-Sheet 1 h Dec. 12, 1939. w. s. WOLFRAM AUTOMOBILE CLUTCH Filed June 14, 1937 2.Sheets-Sheet 2 5 WWW m gg awe/who'l Patented Dec. 12, 1939 PATENT OFFICE AUTOMOBILE CLUTCH William S. Wolfram, Dayton,

General Motors Corporation,

Ohio, assignor to Detroit, Mich., a

corporation of Delaware Application June 14, 1937, Serial No. 148,095

'7 Claims.

This invention relates to friction clutches and has been designed to improve the clutch by which the engine of a motor vehicle drives the input,

take place thereby to reduce the shock of clutch' engagement.

As another object of. the invention uses a resilient element adapted to be compressed in the act of clutch engagement but it is so located that it is removed from the region of the friction facings and therefore is not subjected to the heat generated in the act of clutch engagement. I

Other objects and advantages will be understood from the following description.

In the accompanying drawings, Figure 1 is a transverse section through the novel clutch.

Figure 2 is a view in elevation.

Figure 3 is a section on line 3-3 of Figure 2.

Figure 4 is a section on line 4-4 of Figure 2.

Figure 5 is a section like that of Figure 4 but with the parts differently positioned.

Referring to the several figures of the drawings,

numeral 1 designates a more or less conventional clutch housing within which is seen the end of the crankshaft 9 and the flywheel secured to the shaft by fastening means l3. At I5 is seen the transmission input shaft piloted in the end of the engine shaft by means of bearings H. A clutch cover I9 is secured to the flywheel at 2|. The cover l9 serves as an abutment for a plurality of clutch engaging springs, one of which is shown by numeral 23. These springs are operable to push a pressure plate 25 toward the flywheel and to thereby grip the driven clutch member between itself and the flywheel.

The clutch cover carries a plurality of fulcra such as 21 for pivotal engagement with fingers 29. These-fingers are adapted to rotate in the act of releasing the clutch against the tension of its spring 23. The mechanism for so functioning may be seen in the drawings to include'members .3| threaded into parts of the pressure plate extending through openings 33 in the cover and having heads such as 32 adapted to be engaged by the ends of the fingers29. At 35 is a reciprocable collar adapted to be moved toward the left in Figure 1, to rotate the fingers and thereby pull the pressure plate away from the flywheel. The

lever for reciprocating the collar may be conventional and is not illustrated.

The driven member of the clutch is associated with a hub 31. The hub is non-rotatably carried by the shaft l5. This hub is formed with a flange 4|] preferably provided with recesses 39 through which pass rivets 4|. Between the heads of the rivets and within the openings 39 each rivet has a somewhat enlarged cylindrical part 43. The driven plate'45 is rigidly secured to these rivets between one set of heads and the intermediate parts 43 as clearly shown in Figure 1. Similarly a cooperating plate 41 is secured to the rivets between the parts 43 and the other heads.

7 The axial length of each part 43 is such as to space plates 45 and 41 slightly away from the side walls of flange 40. The dimensions of the recesses 39 and the part 43 of the rivets are such as to provide a limited relative rotary movement between the hub flange 40 and the plates 45 and 41. Plate 41 is formed with an angular axially split part 49 frictionally engaging the hub and pressed thereagainst by a resilient split ring 5|.

Alternating with the recesses 39 in the hub flange 40 are openings 53. The plates 45 and 41 have openings registering with openings 53. Coil springs 55 are assembled in these registering openings. These springs may be retained in place by any convenient lip formations 51 and 59 on the plates 45 and 41. The limited relative rotary motion between the hub flange and the two plates which is made possible as explained above by the clearances within openings 39 is resiliently resisted by the springs 55, this being a known provision for cushioning the drive of such a shaft as l5. During such relative motion friction occurs between the hub and part 49, its intensity determined by pressure of ring 5|.

Plate 41 terminates radially at a point slightly beyond the periphery of the hub flange 40. Driven plate 45 extends outwardly between the flywheel and the pressure plate and carries a 40 facing 6| secured thereto by rivets 63.

A plurality of segmental plates are distributed in a circular series between the plate 45 and the pressure plate. Shoulder rivets 61 extending freely through plate'45 serve to secure to the plates 65 an annular facing 69. By this construction the series, of plates 65 carrying the facing 69 are guided for movement axially toward or away from plate 45, being limited in their movement'of separation by the heads of rivets 1|. This assembly comprising plates 65 andthe facing 69 is in spaced relation from plate 45 when the clutch is released as shown in Figures 3 and 4 and in contact with plate 45 when the clutch is engaged as shown by Figure 5.

Provision is made to resiliently hold the plates apart when the clutch is released, this resilient means opposing the clutch engaging springs 23 and thus preventing the sudden gripping action which might otherwise occur. Expedients intended to perform just such a function are known in the prior art but for the most part they employ resilient means such as spring tongues or the like between the opposed facings. Such springs are therefore located where they are subjected to the heat produced by the frictional engagement of the clutch members. They are thus easily damaged.

To secure an emcient resilient means to oppose the action of the main clutch springs and also to avoid a location of such resilient means between the facings, the following expedient is herein disclosed. Holes of substantially rectangular shape designated by numeral 13 are formed in plate 45, one such hole being opposite each plate 65 and preferably midway between its ends. Within each hole is what may be called a cam plate 75. At one radial edge of the hole 13 the material of plate 35 is'shaped to form a hinge as at TI and the material of the facing 6i and plates 65 are cut away to accommodate parts of the hinge as shown at 19. This hinge allows the cam plate to swing when resiliently energized in a manner to be explained below and thereby push against plate 65 to move it away from plate 45. When the clutch is being engaged and plate 65 is being moved against plate 45 the cam plate is forced into the holes 13 as will be appreciated from a comparison of Figures 4 and 5. An annular spring 8! is normally slightly bowed or coned from a plane surface as shown by Figure 3. This plate 8| surrounds the hub flange 40 and is engaged bya lug 83 offset from an inner corner of cam plate 75 adjacent the edge opposed to the edge which is hinged to plate 45. When the clutch is in released position, the resiliency of this spring ring operating on the lug 83 tilts the cam plate as shown in Figure 3 so that its unhinged edge pushes plate 65 away from plate 45. When the clutch springs are allowed to re-engage the clutch plates 65 obviously move from their spaced relation into contact with plate 45. In so moving the cam plates 15 are forced into the slots 13 and this rotation of the cam plates causes the lugs 83to flatten the spring 8i ther by creating in the spring the potential energy available to again effect the separation when the pressure plate is moved away from the flywheel in the act of clutch release.

By the above construction it will be seen that spring 8| opposes springs 23 and insures a gradual engagement of the clutch members. MOLE- over the location of spring 8| radially within the clutch engaging members is such as to prevent the heat of frictional engagement being transmitted to and thereby injuring the spring 8 I.

I claim:

1. In a clutch, spaced driving members, a driven mem er therebetween, said driven member comprising a driven plate, segmentalplates opposed to the driven plate, facings carried by said driven plate and said segmental plates, re-

silient means radially within said facing and means actuated by said resilient means and extending between said driven plate and segmental plates to space said plates apart when the clutch is relesed.

2. The invention defined by claim 1, said resilient means being a bowed spring annulus.

3. The invention defined by claim 1, said resilient means comprising an annulus of spring metal of conical form in its unstressed condition, and said means actuated thereby comprising a cam plate between each segmental plate and the driven plate, means to hinge one edge of said cam plate, said cam plate having an offset lug adjacent its opposite edge engaging said spring annulus.

4. The invention defined by claim 1, said resilient means being an annulus of spring metal of conical form in its unstressed condition and said means actuated thereby comprising a cam plate between each segmental plate and said driven plate, means to hinge one radial edge of said cam plate to said driven plate, said cam plate having an offset lug adjacent its opposite radial edge and engaging said spring annulus.

5. The invention definedby claim 1, said resilient means being anannulus of spring metal of conical form in its unstressed condition, said driven member having a plurality of apertures, said means actuated by the spring annulus comprising a plurality of cam plates each cam plate hinged at one edge to said driven member and having a lug extending radially from the opposite edge and engaged by said spring annulus whereby the spring annulus may operate through the instrumentality of said cam plates to space the segmental plates from the driven plate and whereby the cam plates may be received into said apertures of the driven plate when the clutch is engaged.

6. In a clutch, spaced driving members mounted for relative axial movement and having opposed annular parallel friction faces, a driven member having substantially parallel parts be-- tween and'adapted to be engaged by said driving friction faces, said last named parts mounted to have relative axial movement, resilient means positioned as an entirety radially within said annular faces and operable to bias said parts to axially spaced relation and spring means to effect engagement of said driving and driven mem bers.

.7. In a clutch, spaced driving members mounted for relative axial movement and having opposed annular friction faces, a driven member having substantially parallel parts between and adapted to be engaged by said driving friction faces, said last named parts mounted'to have relative axial movement and resilient means positioned radially within said annular faces and operable tobias said parts to axially spaced relation, a first one of said parallel parts being an unbroken ring, the other part comprising a ring formed by a plurality of segments, cam plates hinged to the first part and engaging the second parts, said cam plates having lugs engaged by said resilient means.

WILLIAM S. WOLFRAM. 

